Polypropylene stabilized with metal salts of n - hydroxyalkylbenzyl alkylenepolyamines

ABSTRACT

POLYPROPYLENE COMPOSITIONS STABILIZED AGAINST PHOTODEGRADATION BY DIVALENT METAL SALTS OF POLYAMINES HAVING THE FORMULA:   (2-HO,5-R-PHENYL)-CH2-(N(-R&#39;&#39;)-(CH(-R&#34;))Z-CH(-R&#39;&#39;&#34;))Y-   N(-H(2-X))-(CH2-(2-HO-1,5-PHENYLENE))X   WHEREIN R IS AN ALKYL GROUP OF ABOUT 5 TO ABOUT 15 CARBON ATOMS; R&#39;&#39; IS H OR   (2-HO,5-R-PHENYL)-CH2-   R&#34; AND R&#34;&#39;&#39; WHICH MAY BE ALIKE OR DIFFERENT ARE H OR ALKYL GROUPS HAVING LESS THAN 5 CARBON ATOMS EACH; Z IS AN INTEGER IN THE RANGE OF 1 TO 12; Y IS AN INTEGER IN THE RANGE OF 1 TO 4; X IS 0, 1 OR 2 AND THE NUMBER OF MOLS OF DIVALENT METAL PER MOL OF SALT IS IN THE RANGE OF ABOUT 0.5 TO 3.5, INCLUSIVE.

United States Patent 3,678,000 POLYPROPYLENE STABILIZED WITH METAL SALTS OF N HYDROXYALKYLBENZYL ALKYLENEPOLYAMINES John Howard Adams, San Rafael, Califl, assignor to Chevron Research Company, San Francisco, Calif. No Drawing. Application Dec. 6, 1968, Ser. No. 781,996, which is a continuation-impart of application Ser. No. 714,773, Mar. 21, 1968. Divided and this application Sept. 25, 1970, Ser. No. 75,686

Int. Cl. C08f 45/62 US. Cl. 260-4575 N Claims ABSTRACT OF THE DISCLOSURE Polypropylene compositions stabilized against photodegradation by divalent metal salts of polyamines having the formula:

OH OH ll-l) R R x wherein R is an alkyl group of about 5 to about 15 carbon atoms; R is H or CROSS REFERENCE TO RELATED APPLICATIONS This application is a division of John Howard Adams copending application Ser. No. 781,996, filed Dec. 6, 1968, now abandoned, which, in turn, is a continuation-in-part of John Howard Adams US. application Ser. No. 714,- 773, filed Mar. 2], 1968, now abandoned.

FIELD OF INVENTION This invention concerns metal salts of linear alkylcnepolyamines in which at least one of the nitrogen atoms is substituted with a hydroxyand alkyl-substituted benzyl radical and their use as photostabilizers for polypropylene.

DESCRIPTION OF INVENTION The novel stabilizers of this invention are metal salts of polyamines having the formula:

OH OH 3,678,000 Patented July 18, 1972 wherein R is an alkyl group of about 5 to about 15 carbon atoms; R is H or R" and R' which may be alike or different are H or alkyl groups having less than 5 carbon atoms each; 2 is an integer in the range of l to 12; y is an integer in the range of l to 4;andxis 0,1or2.

The preferred compounds of the invention for their effectiveness as photostabilizers for polypropylene are nickel salts of polyamines of the formula:

wherein R is alkyl of about 5 to about 15 carbon atoms, R is H or is an integer in the range of l to 4, inclusive, and x is 0, 1 or 2. Preferably, y is 1 or 2. The number of nickel atoms per mol of salt is in the range of about 0.5 to 3.5, inclusive.

The maximum number of 2-hydroxy-5-alkylbenzyl groups is two plus the number of nitrogen atoms in the salt. Thus, there may be 1 to 7 of such groups present. Two of these groups may be attached to a single nitrogen atom. The alkyl groups (R) may be the same or different. They may be branched or straight-chain. Examples of such alkyl groups are pentyl, hexyl, heptyl, octyl, nonyl, decyl, undccyl, dodecyl, tridecyl, tetradecyl and pentadecyl. Preferred R groups are those having 8 to 15 carbon atoms. Salts wherein R is octyl or dodecyl are particularly preferred because of the availability of their phenolic precursors and their superior polymer compatability and performance as stabilizers.

Salts represented by the above formula are the metal, preferably nickel salts of:

N- Z-hydroxy-S-octylbenzyl) ethylenediamine, N-(Z-hydroxy-S-decylbenzyl) ethylenediamine, N-(2-hydroxy-5-dodecylbenzyl) ethylenediamine, N-(Z-hydroxy-5tridecylbenzyl) ethylenediamine, N,N-di(Z-hydroxy-S-nonylbenzyl) ethylenediamine, N,N'-di(Z-hydroxy-S-dodecylbenzyl) ethylenediamine, N,N-di(2-hydroxy-S-pentadecylbenzyl) ethylenediamine, N-(2-hydroxy5-octylbenzyl)-N'-(2-hydroxy-5-d0decylbenzyl) ethylenediamine, l-(2-hydroxy-5'-octylbenzyl) diethylenetriamine, l-(2'-hydroxy-5-undecylbenzyl) diethylenetriamine, l- 2'-hydroxy-5 '-tetradecylbenzyl) diethylenetriamine, l,4-di(2-hydroxy-5-dodecylbenzyl) diethylenetriamine, l,4-di(2'-hydroxy-S-pentadecylbenzyl) diethylenetriamine, l,7-di(2'-hydroxy-5-decylbenzyl) diethylenetriamine,

4 1-(2'-hydroxy-S'-tetradecylbenzyl)-4-(2"-hydroxy-5"- (hydroxyalkylbenzyl) ethylenepolyamine is neutralized octylbenzyl) diethylenetriamine, with a base, e.g., sodium methoxide, and then a nickel 1,l,4-tri(2'-hydroxy-5'-dodecylbenzyl) diethylenetrisalt as the chloride is added. The resulting organic salt amine, precipitates and is removed by filtration. The by-product l,4,7-tri(2'-hydroxy-5'-tridecylbenzyl) diethylenetrisodium chloride is removed by a water wash.

amine, 5 The nickel compounds formed by the recation of the l,4-di-(2'-hydroxy-5'-decylbenzyl)-7-( "-hydroxy-5" N-(hydroxyalkylbenzyl) ethylenepolyamines and a nickel tetradecylbenzyl) diethylenetriamine, salt have two general type structures. In the first type, l,lO-di(2'-hydroxy-5'-pentylbenzyl) triethylenetetraboth bonds of the divalent nickel are joined to one molemine, cule of the phenolicamino compound. One form of this 1,7,l3-tri(2'-hydroxy-5'-hexylbenzyl) tetraethyleneinternal bonding is illustrated by the following formula:

pentamine, 1,4,7,10,l3-penta-(2-hydroxy-5-octylbenzyl) tetra- H ethylenepentamine, l, l 13,1 B-tetra-(2'-hydroxy-5'-dodecylbenzyl tetraethylenepentamine, 15 1,1,4,7,l0,l-hexa(2-hydroxy-5'-pentylbenzyl) tri- OH OH ethylenetetramine and Nil (2' hydroxy heptylbenzyl) 4 (2" hydroxy- C 5" nonylbenzyl) 7 (2"' hydroxy 5" undecyl- 0 N-H CH, benzyl) 10 (2 hydroxy 5 tridecylbenzyD- I 13 (2' hydroxy 5' pentadecylbenzyl) tetraethyl- 0H: enepentaminc.

Also included are metal, preferably nickel salts of higher alkylene polyamines as follows: CHE N,N- (Z-hydroxy-S-octylbenzyl -pentane l ,S-diamine; N-(Z-hydroxy-S-daoylbonzyl) dodecane-LlZ-diamine; In the second type of compound, the two valences of the N,N'-(Z-hydroxy-S-dodecylbenzyl) propane-1,2-dinickel atom are satisfied by two different molecules of amine; the phenolicamino compound. This results in a larger l,4-di(z-hydroxy-5'-octylbenzyl)-2,5-dimethyldiethylmolecular weight than otherwise expected. One form of enetriamine; this interbonding is illustrated by the formula:

IIz-NII-CIIz-CH1 CHz-CH:NH-CHa- HN\ N-H g \N,l \(EHI C..... -O -c.... l,4,7-tri-(2'-hydroxy-5-tetradecylbenzyl)-2,5,8-triethyl The dotted lines in the above formulas represent nitrogen diethylenetriamine; to nickel coordinate bonds. Many variations of both inter N,N,N',N'-tetra(Z-hydroxy-S-pentylbenzyl-octane-1,8- and intra bonding are possible, and these variations permit diamine. a wide variation in the molar amount of nickel that may be incorporated in the module. At the minimum, with nickel interbonding, one-half mole of nickel combines with one molecule of a phenolic-amino compound. At the other extreme, the number of nickel atoms is one-half the number of phenolic groups in the molecule, e.'g., 3.5 nickel atoms in hepta (2 hydroxy 5 alkylbenzyl) tetraethylenepentamine.

The following examples illustrate various salts of this invention and a specific method for preparing them. These examples are in no manner intended to limit the invention described herein. Unless otherwise indicated, percentages are by weight.

The salts of this invention may be prepared by first preparing the N-(hydroxyalkylbenzyl) alkylenepolyamine compound and then forming its metal salt. The ethylenic phenolic polyamines of the above formula may be made by reacting a linear ethylenepolyamine having 1 to 4 ethylene groups and 2 to 5 nitrogen atoms (ethylenediamine, triethylenetetramine and tetraethylenepentamine), with formaldehyde and a p-alkylphenol wherein the alkyl group contains from about 5 to about 15 carbon atoms. In the case of the higher alkylene polyamines the reaction is the same. The addition sequence of the reactants is not critical within reasonable times and temperatures, and in EXAMPLE I the absence of catalysts. Equimolar amounts of formaldehyde and phenol will be used in the reaction. The number 50 (a) preparation f di (z hydroxy 5 octylbenzyl) of mols of formaldehyde and alkylphenol per mol of ethylenediamine polyamine will be in the range of l to 7, inclusive.

The preparation of these N-(hydroxyalkylbenzyl) In a 250-ml. 3-necked flask fitted with stirrer, reflux alkylenepolyamines will normally be carried out at temcondenser and addition funnel, 20.6 g. of p-octylphenol peratures in the range of about 50 to 100 C. The pres- 55 was heated to about 90 C. Then 3.0 g. ethylenediamine sure is not criticaltherefore autogenous or atmospheric was added and the mixture stirred for 15 minutes at pressures will be used. This preparation may be carried -90 C. Aqueous formaldehyde, 8.1 grams of 37% conout neat (without solvents) or with such solvents as centration, was added dropwise at C. The reaction benzene, toluene, methanol, ethanol, and carbontetramixture was stirred for two additional hours at about 90 chloride, 7 C. At the end of this time, a Dean-Stark adapter was in- The metal salts of these N-(hydroxyalkylbenzyl) sertcd in the reflux condenser and benzene was added to alkylene polyamines as illustrated by the nickel salts of the reac on mixture. Water was removed by the 212cc- N-(hydroxyalkylbenzyl) ethylenepolyamines may bg ll'OplC distillation with benzene. After all Of the water formed by reacting the phenolic polyamines with a nickel was m the reaction mlXtUfe W35 POUffid fll a salt, preferably an inorganic nickel salt. First the N- 75 container and dried to a constant weight of 26.6 g. The

light yellow, thick, oil-like product had the following element analysis.

Calculated for C H N O C, 77.4; H, 10.5; N, 5.6; M.W., 496. Found: C, 77.5; 11-1, 10.3; N, 5.5; M.W., (ThermoNAM method) 545.

The infrared spectrum of this product had a small peak at 3600 cm." a broad peak centered at 3300 CHI-"1, a large peak at 2940 cm? and a medium sized doublet at 1600 cmr An NMR spectrum was obtained of this product dis 6 Ni, 10.6; M.W. 553. Found: C, 67.29; H, 9.49; N, 4.61; Ni, 8.54; M.W. 915.

The infrared spectrum of this salt differs somewhat from that of the parent compound; particularly in the lower intensity of 3300 cm.- band and the conversion of the doublet band at 1600 cm.- to a broad, strong single peak.

Other nickel salts of this invention were prepared by the general method described in Example 1. These nickel salts are listed in Table I.

solved in deuterated chloroform (CD01 This spectrum TABLE I Mole ratio, NiClrfiHrO/ Polyamlne p-Alkylphenol phenollclpolyamine Product analysis wt. percent Amt. Amt. In the In the Mol Example No. Type (g). Type (g.) reaction product wt. 0 H N Ni 78. 6 2.0/3. 0/l.0 1.3/2.1/L0 1, 100 67.0 8. 8 l5. 4 10.0

37% formalin solution used in equal molar amounts to alkyl phenol Dodocyl is a propylene tetramer.

Norr:.-E DA Ethylenediamlnc. D ETA Diethylenetriamine. Dlpropylene triamlne. PDA= Propancdiamine. ODA Octanediarnlne.

had singlet proton peaks at 0.68, 1.29, 1.64, 2.71, 3.61, 3.84, and 6.23 (broad) and a multiplet at 6.6 to 7.2 p.p.m. in reference to tetramethylsilane. The area under these peaks was proportional to the number of protons in either N,N- or N,N-di(2-hydroxy-5-octylbenzyl) ethylenediamine. The presence of a peak at 3.6 p.p.m. and at 3.8 p.p.m. (the region of resonance of a proton of a methyl ene group located between an aryl group and a nitrogen atom) indicates that the product is a mixture of both of these compounds.

A mass spectrum analysis of the product showed that there were two large mass ion peaks at 247 and 465. These peaks results from the following two fragments:

o H on o as Hg-NII=CHg on. N=C n, i and 1 sHn a n This analysis also indicates that the product of the experiment is a mixture of N,N-di(2-hydroxy-5-octylbenzyl) ethylenediamine and N,N'-di(Z-hydroxy-S-octylbenzyl) ethylenediamine.

(b) Preparation of the nickel salt of di(2hydroxys-octylbenzyl) ethylenediamine The product (2.5 g.) of Example la was dissolved in methanol containing 0.54 g. sodium methoxide and heated to reflux for one-half hour. After cooling to room temperature, 1.20 g. nickelous chloride hydrate in methanol was added and the mixture was stirred for an additional one-half hour at 25 The reaction mixture was then poured into water. The resulting precipitate was filtered and washed with water until no more chloride ion was detected in the wash water by aqueous silver nitrate. The product was then dried to a constant weight of 2.55 g. in a vacuum oven. The resulting light green powder had a M.P. 120-155 C. Its element analysis was:

Calculated for C H N O Niz C, 69.5; H, 9.1; N, 5.1;

TETA=Trlethylenetetrarnlne TEPA=='Ietraethylenepentamlne. DPTA= UTILITY The salts of this invention have exhibited an ability to enhance the resistance of substantially crystalline polypropylene to photodegradation caused by exposure to ultraviolet light. Accordingly, these salts will be mixed homogeneously with such polypropylene at concentrations of at least about 0.05 wt. percent, usually about 0.05 to 0.50 wt. percent, based on the polypropylene, to enhance the photostability of the polypropylene. This mixing may be achieved by blending the polymer and salt in powder form in conventional powder blenders or by mixing them in conventional melt blenders. Minor amounts of other polymers, pigments, other photostabilizers, oxidation stabilizers, heat stabilizers, dye acceptors, dyes, fillers, and the like may also be incorporated into these mixtures.

The normally solid, substantially crystalline polypropylene which is stabilized by the salts of this invention is a well known, commercial commodity. It is normally at least about crystalline. It is essentially insoluble in refluxing heptane.

The salts of the above examples were tested as photostabilizers for polypropylene by the following procedure. 0.010 g. of 2,6-di-t-butyl-p-cresol and 0.050 g. of the nickel stabilizer were dissolved in acetone and poured into 10.0 g. of a commercial, unstabilized polypropylene powder. The slurry was stirred thoroughly until absolutely dry. The slurry was them mold pressed at 475 F. and up to 30,000 p.s.i. into a 20 mil sheet. This sheet was cut into 1-inch by 2-inch samples which were exposed to an ultraviolet energy source (450 watt mercury vapor lamp). The samples were periodically examined in the 1800- 1600 cm.- region of the infrared spectrum for carbonyl (oxidation) buildup using an unexposed sample in the reference beam. The sample was also periodically flexed to determine whether it had failed by embrittlement. Table II reports the results of these tests. For comparison, a sample without an ultraviolet light stabilizer and samples of other phenolic nickel salts were also tested by the above procedure. These comparison tests are reported in Table II.

TABLE II Carbonyl buildup (infrared absorbance) 30 hrs. 100 hrs.

17 No UV light stab ize Commercial 1 Ni salt of p-octyl phenol l The nickel salt of bis(p-octylphenol)sulfido.

The nickel salts of the present invention shOW synergistic stabilization of polypropylene when combined with hindered phenols conventionally used as ultraviolet light stabilizers. For instance, mixtures of nickel salts of this invention with 2-hydroxy-4-octyloxybenzophenone or 2- (2'-hydroxy-3',S-d t butylphenol) S chlorobenzotriazole gave better UN. stability than the individual compounds at equal concentrations.

Although the nickel salts of N-(hydroxyalkylbenzyl) ethylene polyamines in accordance with this invention are preferred for their effectiveness in stabilization of substantially crystalline polypropylene, other metal salts are effective as shown in Table III.

The various metals were tested by preparing the corresponding organometallic stabilizer from N,N'- bis(2 hydroxy 5 tetrapropylbenzyl)ethylenediamine, (R=C H R=H, y: l, and x=l). Each of these test compounds was mixed with polypropylene powder at a concentration of 0.50%. At the same time, 2,6-di-t-butylp-cresol (BHT) was also mixed in at a concentration of 0.10%. The dry mixture was pressed into 20-min. thick sheets. These sheets were exposed to a fluorescent sun lamp-black light Weather-Ometer and analyzed periodically by infrared for carbonyl buildup. The sheets were also flexed to obtain a time to flexural failure.

While the character of this invention has been described in detail with numerous examples, this has been done by way of illustration only and Without limitation of the invention. It will be apparent to those skilled in the art that modifications and variations of the illustrative examples may be made in the practice of the invention within the scope of the following claims.

I claim:

1. Composition comprising normally solid, substantially crystalline polypropylene and divalent metal salt of polyamines having the general structure illustrated by formulae selected from the group consisting of wherein M is divalent metal, R is an alkyl group of about 5 to about 15 carbon atoms; R is H or R" and R' which may be alike or different are H or alkyl groups having less that 5 carbon atoms each; z is an integer in the range of l to 12; and the number of mols of divalent metal per mol of salt is in the range of about 0.5 to 3.5, inclusive, said divalent salt being present in an amount sufficient to enhance the photostability of the polypropylene.

2. Composition comprising normally solid, substantially crystalline polypropylene and nickel salt of the formulae of claim 1 in an amount sufficient to enhance the photostability of the polypropylene.

3. Composition comprising normally solid, substantially crystalline polypropylene and at least about 0.05 wt. percent of the nickel salt of the polyamine of claim 2.

4. Composition comprising normally solid, substantially crystalline polypropylene and about 0.05 to about 0.5 wt. percent of the nickel salt of the polyamine of claim 2.

5. Composition comprising normally solid, substantially crystalline polypropylene and divalent metal salt of polyamines having the formula Oll wherein R is an alkyl group of about 5 to about 15 polypropylene, and the divalent metal of said salt being carbon atoms; R is H or principal valence bonded entirely to the phenolic oxygen.

t References Cited --CH1 5 FOREIGN PATENTS 994,260 6/1965 Great Britain 26045.75

DONALD E. CZAJA, Primary Examiner R and R' which may be alike or different are H or 10 HOKE Assistant Exammer alkyl groups having less than 5 carbon atoms each; z is US Cl.

an integer in the range of 1 to 12; y is an integer in the range of 1 to x is 0 1 or 2 and the number of mols R, C, K, A, R, 45.95,

of divalent metal per mol of salt is in the range of about 429 435 0.5 to 3.5, inclusive, said divalent salt being present in 15 570-5 an amount sufficient to enhance the photostability of the 

